(1) Field of the Invention
One aspect of the invention relates to an impact-absorbing helmet with a compliant liner system that absorbs energy generated by an impacting force exerted on the outside of the helmet and reverts toward an un-deflected, non-destroyed configuration after impact.
(2) Description of Related Art
Helmets and hard hats have been used for centuries in all types of activity where there is a risk of blunt force trauma to the head. These helmets will typically consist of three layers. The outer shell layer functions to protect the head from lacerations and abrasions from the incident object impacting the helmet. A comfort layer, which contacts the skull of the wearer, typically provides some level of padding to improve comfort and fit of the assembly to the skull. Interposed between the shell and the comfort layer, an energy absorbing system is often utilized to mitigate some of the impacting forces from the blunt force trauma. Often, for example in professional cycling, the helmet will need to be replaced after a blow is sustained
In recent years, Mild Traumatic Brain Injury (MTBI) and concussions have gained more attention since the occurrence of these events do not seem to be decreasing markedly as the helmet technology has improved. Athletes, soldiers, and workers involved in one or more impact events often have short term or permanent loss of brain function as a result of these impact events. NOCSAE, FMVSS, and other helmet system performance standards have sought to improve the performance of helmet systems to reduce the severity of an impact event. However, consumers desire a helmet that not only protects them from the adverse effects of repeated hits, but one that is also aesthetically pleasing, non-restrictive, light weight, comfortable, breathable, safe, durable, and affordable. A helmet may provide exceptional impact protection but if it looks, smells, or feels uncomfortable then no one will wear it.
Helmet manufacturers such as Riddell, Schutt, CCM, Brine, Skydex, Gentex and the like provide helmet systems for various occupations and recreational sports. The outer shell of the helmet is designed in such a way that it protects the wearer from cuts and abrasions from the incident object. These shells are typically thermoplastic or thermoset composites that are extremely tough and rigid. During an impact event, the shell itself does absorb some of the impact energy by flexing in response to the impacting object. However, the majority of the impacting force is transferred from the shell into the shell cavity where the energy absorbing and comfort layers reside and ultimately are transferred to the wearer. This force transfer without significant absorption often presents a risk of injury.
Traditionally, the energy absorbing layer in the shell has been some type of foam assembly. The assembly may be comprised of one or more layers or grades of foam to provide both comfort and impact protection. The inner layer is typically lower in density and provides less energy absorbing contribution than the more rigid outer layer. Furthermore, some systems, such as Riddell's Revolution football helmet, also employ a bladder system that allows the wearer to customize the fit of the helmet to the skull based on the level of liner inflation. While these systems may be comfortable to wear, foam lacks energy absorbing efficiency. Furthermore, foam does not breathe well and its solid construction allows minimal room for airflow to cool the head.
More recently, helmet manufactures have been developing helmet liner systems constructed with a tougher energy absorbing layer made from thermoplastic resins. These materials are typically injection molded or twin sheet thermoformed as an energy absorbing layer. A separate system is utilized to provide comfort to the wearer. The energy absorbing structures, by design, are rigid and uncomfortable. One or more layers of comfort foam or padding is typically added to the assembly. This increases the cost of these systems. Furthermore, the manufacturing methods employed to produce the energy absorbing layer do not allow for a high degree of design flexibility to optimize performance.
Among the prior art considered in preparing this patent application is:
Assignee NameUSPN/App #TechnologyRiddell7,954,177FoamBrine7,908,678FoamXenith7,895,681TPUTeam Wendy6,453,476FoamGentex7,958,573FoamMorgan7,802,320FoamCrescendo7,676,854PlasticSkydex6,777,062TPU
Additionally, several of Applicant's patents (see, e.g., U.S. Pat. Nos. 6,199,942; 6,247,745; 6,679,967; 6,682,128; 6,752,450; 7,360,822; 7,377,577; 7,404,593; 7,625,023 which are incorporated herein by reference) describe an efficient modular tunable energy absorbing assembly for reducing the severity of an impact event.